RFR: 8213325: (props) Properties.loadFromXML does not fully comply with the spec

[Roman Kennke]

This is a backport of:

https://bugs.openjdk.java.net/browse/JDK-8227274

which is a backport of the original:

https://bugs.openjdk.java.net/browse/JDK-8213325

It's mostly the original change with a few significant extra modifications:

-
src/share/classes/sun/util/xml/META-INF/services/sun.util.spi.XmlPropertiesProvider

is changed from:
sun.util.xml.PlatformXmlPropertiesProvider

to:
jdk.internal.util.xml.BasicXmlPropertiesProvider

The reason is that the fix is for the latter, but 8u uses the former by
default. As far as I understand, the latter uses the new slimmer parser,
while the former uses the fullblown XML parser, but I am not sure about
that. However, we need to consider this, because it might be a very
significant change.

The alternative would be to port over the fixes to the other XML parser,
which I have no desire to do.

- The (test) JAR file:
test/java/util/spi/ResourceBundleControlProvider/rbcontrolprovider.jar

has been regenerated from the modified sources XmlRB.xml and XmlRB_ja.xml.

This is not present in jdk11 and later. I think it's generated on the
fly and not checked-in.

Webrev:
http://cr.openjdk.java.net/~rkennke/JDK-8213325/webrev.00/

Testing: New testcases are passing. No regressions in tier1 tests.

Opinions? Can I get reviews?

Thanks,
Roman